In structured illumination microscopy (SIM), the unknown cellular ultra-structure is elucidated by analyzing the moire pattern produced when illuminating the specimen with a known high-frequency patterned illumination. Nikon¡¯s Structured Illumination Microscope (N-SIM) realizes super resolution of up to 115 nm in multiple colors. In addition, it can continuously capture super-resolution images at a temporal resolution of 0.6 sec/frame, enabling the study of dynamic interactions in living cells.

Live-cell imaging at double the resolution of conventional optical microscopes

N-SIM provides ultra fast imaging capability for Structured Illumination techniques, with a time resolution of up to 0.6 sec/frame, which is effective for live-cell imaging (with TIRF-SIM/2D-SIM mode; imaging of up to approximately 1 sec/frame is possible with Slice 3D-SIM mode).

This mode captures super-resolution 2D images at high speed with incredible contrast. TIRF-SIM mode takes advantage of Total Internal Reflection Fluorescence observation at double the resolution as compared to conventional TIRF microscopes, facilitating a greater understanding of molecular interactions at the cell surface.

LU5 N-SIM 5 Laser Module is a modular system with up to five lasers enabling true multi-color super resolution. Multi-color capability is essential to the study of dynamic interactions of multiple proteins of interest at the molecular level.

Analytical processing of recorded moire patterns produced by overlay of a known high spatial frequency pattern, mathematically restores the sub-resolution structure of a specimen.

Utilization of high spatial frequency laser interference to illuminate sub-resolution structure within a specimen produces moire fringes, which are captured. These moire fringes include modulated information of the sub-resolution structure of the specimen.
Through image processing, the unknown specimen information can be recovered to achieve resolution beyond the limit of conventional optical microscopes.

An image of moire patterns captured in this process includes information of the minute structures within a specimen. Multiple phases and orientations of structured illumination are captured, and the displaced "super resolution" information is extracted from moire fringe information. This information is combined mathematically in "Fourier" or aperture space and then transformed back into image space, creating an image at double the conventional resolution limit.

The capture of high resolution, high spatial frequency information is limited by the Numerical Aperture (NA) of the objectives, and spatial frequencies of structure beyond the optical system aperture are excluded (Fig. A). Illuminating the specimen with high frequency structured illumination, which is multiplied by the unknown structure in the specimen beyond the classical resolution limit, brings the displaced "super resolution" information within the optical system aperture (Fig. B).
When this ¡°super-resolution¡± information is then mathematically combined with the standard information captured by the objective lens, it results in resolutions equivalent to those captured with objective lenses with approximately double the NA (Fig. C).

Objectives for super-resolution microscopes

The SR (Super Resolution) objectives have been designed for new applications that break the diffraction barrier.
The most recent optical designs and the best selection of optical glasses have been applied to yield optical performances with the lowest possible remaining spherical and cylindrical aberrations.